Final answer:
The student's question regarding marginal and total utility is addressed with explanations for each unit of good X consumed. It demonstrates how marginal utility decreases with each additional unit, which is an example of the law of diminishing marginal utility.
Step-by-step explanation:
The question posed falls under the subject of Economics, and it deals with the concept of the marginal utility and total utility in the context of consumer behavior. Marginal utility refers to the additional satisfaction a consumer receives from consuming one more unit of a good or service, whereas total utility is the overall satisfaction received from consuming a certain quantity of goods or services.
The marginal utility of the first unit of good X is 4, as that is the total utility derived from consuming one unit. For the second unit, the increase in total utility is from 4 to 10, thus the marginal utility of the second unit is 6 (10-4). Similarly, the marginal utility of the third unit is 8, as the total utility jumps from 10 to 18 (18-10). The fourth statement regarding the total utility for four units cannot be verified without additional information, as the increase in utility beyond the third unit is not provided.
The concept of diminishing marginal utility is key here, representing the idea that the satisfaction from consuming additional units tends to decrease. This decrease is observed in practice and is a fundamental principle in Economics, akin to the law of diminishing returns.